tests/testthat/test_fill-holes.R

In smoothr: Smooth and Tidy Spatial Features

context("fill_holes()")
skip_on_os("solaris")

library(sf)
library(units)

test_that("fill_holes() works", {
  p <- jagged_polygons$geometry[5]
  # remove hole
  p_filled <- fill_holes(p, threshold = units::set_units(1000, km^2))
  expect_true(st_area(p) < st_area(p_filled))
  # don't remove hole
  p_filled <- fill_holes(p, threshold = units::set_units(100, km^2))
  expect_true(st_area(p) == st_area(p_filled))
})

test_that("fill_holes() doesn't alter polygons with no holes", {
  p <- jagged_polygons[!jagged_polygons$hole, ]
  p_filled <- fill_holes(p, threshold = units::set_units(1e12, km^2))
  expect_equivalent(p, p_filled)
})

test_that("fill_holes() works for different input formats", {
  jp <- jagged_polygons[5:6, ]
  s_sf <- fill_holes(jp, threshold = 2e8)
  s_sfc <- fill_holes(st_geometry(jp), threshold = 2e8)

  jp_sp <- as(jp, "Spatial")
  sp::proj4string(jp_sp) <- st_crs(jp)$proj4string

  s_spdf <- fill_holes(jp_sp, threshold = 2e8)
  s_sp <- fill_holes(as(jp_sp, "SpatialPolygons"), threshold = 2e8)
  expect_s3_class(s_sf, "sf")
  expect_s3_class(s_sfc, "sfc")
  expect_s4_class(s_spdf, "SpatialPolygonsDataFrame")
  expect_s4_class(s_sp, "SpatialPolygons")
  a_diff <- st_area(s_sf) - st_area(s_sfc)
  expect_true(sum(abs(a_diff)) < units::set_units(1, "m^2"))
  a_diff <- st_area(s_sf) - st_area(st_as_sf(s_spdf))
  expect_true(sum(abs(a_diff)) < units::set_units(1, "m^2"))
  expect_equivalent(st_set_geometry(s_sf, NULL), s_spdf@data)
})

test_that("fill_holes() works for SpatVector objects", {
  skip_if_not_installed("terra")
  jp <- jagged_polygons[5:6, ]
  jp_terra <- terra::vect(jp)
  s_terra <- expect_warning(
    fill_holes(jp_terra, threshold = units::set_units(1000, km^2))
  )
  expect_s4_class(s_terra, "SpatVector")

  a_diff <- terra::expanse(jp_terra) - terra::expanse(s_terra)
  expect_lt(a_diff[1], 0)
  expect_equal(a_diff[2], 0)
})

test_that("fill_holes() fails for points and lines", {
  point <- st_point(c(0, 0)) %>%
    st_sfc()
  expect_error(fill_holes(point, threshold = 1))
  expect_error(fill_holes(as(st_sfc(point), "Spatial"), threshold = 1))

  expect_error(fill_holes(jagged_lines, threshold = 1))
  expect_error(fill_holes(as(jagged_lines, "Spatial"), threshold = 1))
})

test_that("fill_holes() fails for invalid thresholds", {
  expect_error(fill_holes(jagged_polygons, threshold = -1))
  expect_error(fill_holes(jagged_polygons,
                          threshold = set_units(1, "km")))
})

test_that("fill_holes() does nothing when threshold = 0", {
  p_filled <- fill_holes(jagged_polygons, threshold = 0)
  expect_identical(jagged_polygons, p_filled)
})